1. Field of the Invention
The present invention relates to a liquid crystal composition containing a solid matter having a specified size, a dichroic dye having a specified substituent and a host liquid crystal; and a display device using the liquid crystal composition.
2. Description of the Related Art
High visibility and low electric power consumption are characteristics that are required in display devices. A guest-host display device is known as a liquid crystal device (liquid crystal display device) which satisfies the above-mentioned requirements. Such a display device can achieve bright display and is expected to be used as a display device suitable for a reflective display device.
For instance, a liquid crystal composition comprising a dichroic dye having a specified substituent and a host liquid crystal, and a guest-host display device using the composition have been disclosed (see, for example, Japanese Patent Application Laid-Open (JP-A) No. 2004-75821).
On the other hand, a guest-host display device comprising a clay compound as an inorganic compound having a submicron size, a nematic liquid crystal and a dichroic dye has been proposed (see, for example, JP-A No. 7-318982).
However, further improvement in display performance, particularly in visibility, is still demanded.
With the objectives of realizing a light absorption state which is independent of polarization and providing a memory function in a guest-host reflective display device, the inventors of the present invention examined a system wherein a solid matter having a submicron size is mixed into a host liquid crystal with a dichroic dye. As a result, the inventors of the present invention newly found problems such as a low order parameter of the dichroic dye and a deterioration in display performance caused by the dichroic dye being absorbed by the surface of the solid matter.
Further, the inventors of the present invention found an unexpected effect; namely, that when a dichroic dye having a specified substituent is used, the adsorption of the dichroic dye to the solid matter is suppressed, and the performance, especially the display performance, is improved. A further study was then made based on these findings to complete the invention.